Double thread detector

ABSTRACT

A signal generated in response to the presence of a double thread and a signal generated in response to the position of the separated thread provide inputs to an OR/NOR gate. The presence of either input provides an OR output to open a circuit controlling the power supply to a motor.

United States Patent [191 Townsend Oct. 15, 1974 DOUBLE THREAD DETECTOR 3,199,339 8/1965 Lipski 28/64 x [75] Inventor: Franklin L. Townsend, Rockford, 02;

[73] Assignee: Barber-Colman Company,

Rockford, [IL Primary ExammerLou1s K. Rlmrodt Attorney, Agent, or FirmA. Richard Koch [22] Filed: Mar. 30, 1973 [21] Appl. No.: 346,261

Related US. Application Data [57] ABSTRACT [62] Division of Ser. No. 173.852, Aug. 23, 1971,

flbandoned- A signal generated in response to the presence of a double thread and a signal generated in response to [52] US. Cl. 28/43 th sition of the eparated thread provide inputs to Cl. an gate The presence of either input pro- [58] Field of Search 28/43, 46, 49-53, id an OR Output to Open a i it t olling the 28/64, 1 16/65 power supply to a motor.

[56] References Clted 11 Claims, 4 Drawing Figures UNITED STATES PATENTS Fleischer 28/43 PAIENIEmm 1 51914 {\VENTOR. Fran/Win L. Townsend /ZM/ZC/ AGENT DOUBLE THREAD DETECTOR CROSS REFERENCE This application is a division of my copending application Ser. No. 173,852, filed on Aug. 23, 1971, now abandoned.

BACKGROUND OF THE INVENTION This invention relates to improvements in apparatus for separating single threads from a warp sheet. The apparatus is particularly suitable for use in conjunction with tying machines, but may also find application'in drawing-in machines, lease forming machines and the like.

In a warp tying machine the threads of an exhausted warp sheet are tied to corresponding threads of a new warp sheet. This involves separating the outside thread from each sheet and tying together the separated threads. Mechanisms for accomplishing this operation is well known, an examplebeing disclosed by Howard D. Colman in U.S. Pat. No. 977,166, issued Nov. 29, 1910. Occasionally two threads are separated instead of one. Unless this error is promptly caught and corrected, two threads from one sheet will be tied to one thread from the other sheet, resulting in defective cloth being woven. Various methods and apparatus have been devised for detecting double threads, but they have not proven entirely satisfactory. Some rely entirely upon a thread engaging notch -in a picker, or

equivalent member, sized to retain only one thread.

Such devices may not detect double threads when one thread lies above another.

SUMMARY OF THE INVENTION This invention provides a method and apparatus for detecting plural threads separated in error from a sheet of threads. The separated thread is moved to apredetermined position where presence of plural separated threads produces a signal employed to stop further operation of the thread separator and associated appara' tus.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is'a perspective view of a preferred embodiment of the plural thread detector applied to a warp tying machine. v

FIG. 2 is a perspective view of a portion of the thread detectorshowing details of the structure.

FIG. 3 is a schematic view of the fluidic and electric circuits employed in the preferred embodiment.

FIG. 4 is a detail showing the effect of a plural thread.

DESCRIPTION OF THE PREFERRED EMBODIMENT The preferred embodiment for use on a warp tying machine is shown in the drawings. An upper warp sheet 1 comprises the tail ends of the old warp in a loom (not shown) at the left. A lower warp sheet 2 comprises the supply ends of new warp from a beam (not shown) at the left. The threads, all of the same count, comprising these sheets are to be tied respectively together so that weaving of cloth may be continued on the loom. Warp clamps (not shown) hold the sheets in fixed position. A pair of selector fingers 3 and 4 are moved to engage in grooves 5 and 6, respectively, the outer warp threads 7 and 8 of warp sheets 1' and 2, before moving to positions 3a and 4a, thus separating the outer threads from the remainder of the warp sheets and moving them toward each other to positions 7a and 8a shown in dotted lines in FIG. 3. In the positions 7a and 8a the separated threads are engaged by a fork 9 on a separator slide 10, reciprocating on the frame 11 of the warp tying ma chine between warp sheets 1 and 2 and transverse to the threads comprising the sheets, and moved into a thread guide 12 to position the threads at 7b and 8b for tying by the knotter 13 (only partially shown). A second fork l4on the slide 10 similarly moves the separated threads between the jaws of a shear 15, actuated by the slide to sever the threads from the warp clamps (not shown) at the right. The description so far has been concerned with a well-known warp tying machine and its operation.

The body 17 of the plural thread detector is mounted on the frame 11 of the warp tying machine and has a tapered nose 18 adapted to guide the separated outer threads 7 and 8 respectively to opposite surfaces 19 and 20 on the body. In these surfaces are notches 21 and 22, at least a portion,'such as 21a of notch 21, has a cross-section only large enough to accept one separated thread, identified in FIG. 4 as 7c. Between the nose l8 and notches 21 and 22 is a hole 23 drilled through the body 17 from surface 19 to surface 20, forming nozzles 24 and 25 at the respective surfaces. A cross-drilled hole, intersecting the hole 23, provides a connection 26 to a source of air pressure. A sensor 27, shown as a leaf spring mounted at one end 28 on the body 17, is normally biased into contact with surface 19 overlying the notch 21 and nozzle 24, the leaf spring serving both as sensor and biasing means. The free end 29 overhangs the tapered nose 18. A similar sensor 30 is similarly located onsurface 20. The separated threads 7a and 8a are moved by the forks 9 and 14 between the nose 18 and respective sensors 27 and 30, over the surfaces 19 and 20, and into gauging position at the notches 21' and 22 respectively, where the threads are identified as and 84?. When a separated thread 7d in FIG; 4 is between the sensor 27 and surface 19 and not entirely within the notch 21, the sensor is held in a position separated from the nozzle 24 so that the latteris-open, allowing air supplied through connection 26 and hole 23 to escape. The surface 19, notch 21 and sensor 27 constitute a plural thread detector, a similar detector comprising surface 20, notch 22 and sensor 30. It will be seen that each plural thread detector is a GO/NO-GO gage providing a G0 signal when its nozzle 24 or 25 is closed and a NO-GO signal when the nozzle is open. The signals from the separate detectors are shown as summed to provide a composite GO signal when both nozzles 24 and 25 are closed and a composite NO-GO signal when either nozzle is open. In order to prevent an unwanted NO-GO signal while the separated threads 7a and 8a are being moved toward the notches 21 and 22, an overriding signal must be provided. A third nozzle 32 in body 17 is supplied with air pressure through a connection 33,- and is normally maintained closed by a plate 34, shown as another leaf spring mounted at end 35 and having a free end 36. The plate 34 is displaced to open nozzle 32 after the separated threads 7c and have been moved into gauging positions in the notches 21 and 22. As shown in FIGS. land 3, this is accomplished by a plow cam 37 movable with the separator slide 10 to a position 37a, where it lifts the free end 36 to position 36a after the threads 70 and 80 have been moved into the notches.

As shown in FIG. 3, compressed air is delivered through a main 38 to the supply port 39 of an OR/NOR fluidic gate 40, and through restrictors 41 and 42 to the connectors 33 and 26 respectively and to the respective input ports 43 and 44. When either of the nozzles 24 and 25 is open, the air passing through restrictor 42 escapes through the open nozzle as a NO-GO signal and none flows through input port 44. When nozzle 32 is open, the air passing through restrictor 41 escapes through the open nozzle as a NON-INHIBIT signal and none flows through input port 43. In the absence of air flowing through either of the input ports 43 and 44, air entering the OR/NOR gate 40 through supply port 39 leaves through an output port 45, where the resulting NOR signal has no effect upon the described controls. If both of the nozzles 24 and 25 are closed by the sensors 27 and 30, the air passing through restrictor 42 flows through input port 44 as a G signal, diverting the air entering at supply port 39 to an output port 46 as an OR signal. If nozzle 32 is closed by plate 34, the air passing through restrictor 41 flows through input port 43 diverting the air entering at supply port 39 to the output port 46 as an OR signal. Thus, when air flows through either of the input ports 43 and 44, an OR signal is obtained. Either or both of the OR and NOR signals may be utilized as control signals. As shown, the air diverted to the output port 46 as an OR signal is delivered to a pressure switch 47, having a pair of contacts 48 and 48 therein. As shown the contacts 48 and 49 are normallyheld separated by biasing spring 50 and are closed by the pressure of air delivered as said OR signal to the switch. The contacts 48 and 49 are in series with an electric motor 51 across an electric power supply line, so that the motor is energizedwhile the contacts are closed anddeenergized when the contacts are open. The motor 51 supplies mechanical power to operate the warp tying machine.

It will be seen that when a separated plural thread is detected, a NO-GO signal is generated along with a NON-INHIBIT signal, which together producea NOR signal to deenergize the motor and stop the machine. After the condition has been corrected, the machine is restarted, such as by manually closing the contacts 48 and 49. I

While only one embodiment has been described, it will be evident that many modifications are possible. It would, for example, be possible to substitute a pneumaticpressure control, an electrical control or an electronic control for the fluidic control described. The invention is defined by the claims.

I claim: I

1. For use with apparatus intended automatically to sequentially separate single threads from a warp sheet of threads of predetermined count, a device for detect-. ing separated plural threads, said device comprising a rigid body, a surface on said body, a notch in said surface, a'sensor overlying the surface, means biasing the sensor-to a position adjacent the surface, said notch sized to accept beneath the sensor in said adjacent position only one of the separated threads, said sensor held in a position separated from said surface by said separated plural threads between the surface and the sensor. I

2. A device according to claim 1 additionally comprising means for producing a NO-GO signal in response to the separated position of said sensor.

3. A device according to claim 2 additionally comprising means for inhibiting said NO-GO signal until said separated thread is at said notch.

4. A device according to claim 2 additionally comprising'control means responsive to the NO-GO signal to prevent operation of said apparatus.

- 5. A device according to claim 2 wherein said means for producing the NO-GO signal comprises a nozzle and means for connecting the nozzle to a pressure source, said sensor overlying the nozzle whereby said nozzle is closed by the sensor in the adjacent position to produce a G0 signal and opened by said sensor in the separated position to produce said NO-GO signal.

6. A plurality of devices according to claim 5 and means for summing the GO and NO-GO signals produced by the devices to produce a composite GO signal in response to production of said GO signals by each of the devices and to produce a composite NO-GO signal in response to production of said NO-GO signal by any of the devices.

7. A device according to claim 5 additionally comprising a pressure operated switch, a pair of contacts movable between open and closed relationship'in said switch, means biasing said contacts'toward one of said relationships in presence of one of said GO and NO-GO signals, and means responsive to another of said GO and NO-GO signals for applying pressure to move the contacts to another of said relationships.

8. A device according to claim 5 additionally comprising a second nozzle, means connecting the second nozzle to said pressure source, a plate overlying the second nozzle, means normally maintaining said plate in a position closingthe second nozzle to produce an INHIBIT signal, and-means for displacing the plate to open said second nozzle when the separated thread is at the notch to produce a NON-INHIBIT signal.

9. A device according to claim 8 additionally comprising means providing a control signal in response to presence of both of said NO-GO and NON-INHIBIT signals.

10. A device according to claim 8 additionally comprising means providing a control signal in response to presence of at least one of said GO and INHIBIT signals.

11. A device according to claim 8 additionally comprising an OR/NOR fluidic gate having a supply port for connecting the gate to said pressure source, a first input port connected to receive said GO and NO-GO signals, a second input port connected to receive the INHIBIT and NON-INHIBIT signals, a first output port delivering an OR signal from the supply port in presence of at least one of said GO and INHIBIT signals, and a second output port delivering a NOR signal from the supply port in response to presence of both of said NO GO and NON-INHIBIT signals. 

1. For use with apparatus intended automatically to sequentially separate single threads from a warp sheet of threads of predetermined count, a device for detecting separated plural threads, said device comprising a rigid body, a surface on said body, a notch in said surface, a sensor overlying the surface, means biasing the sensor to a position adjacent the surface, said notch sized to accept beneath the sensor in said adjacent position only one of the separated threads, said sensor held in a position separated from said surface by said separated plural threads between the surface and the sensor.
 2. A device according to claim 1 additionally comprising means for producing a NO-GO signal in response to the separated position of said sensor.
 3. A device according to claim 2 additionally comprising means for inhibiting said NO-GO signal until said separated thread is at said notch.
 4. A device according to claim 2 additionally comprising control means responsive to the NO-GO signal to prevent operation of said apparatus.
 5. A device according to claim 2 wherein said means for producing the NO-GO signal comprises a nozzle and means for connecting the nozzle to a pressure source, said sensor overlying the nozzle whereby said nozzle is closed by the sensor in the adjacent position to produce a GO signal and opened by said sensor in the separated position to produce said NO-GO signal.
 6. A plurality of devices according to claim 5 and means for summing the GO and NO-GO signals produced by the devices to produce a composite GO signal in response to production of said GO signals by each of the devices and to produce a composite NO-GO signal in response to production of said NO-GO signal by any of the devices.
 7. A device according to claim 5 additionally comprising a pressure operated switch, a pair of contacts movable between open and closed relationship in said switch, means biasing said contacts toward one of said relationships in presence of one of said GO and NO-GO signals, and means responsive to another of said GO and NO-GO signals for applying pressure to move the contacts to another of said relationships.
 8. A device according to claim 5 additionally comprising a second nozzle, means connecting the second nozzle to said pressure source, a plate overlying the second nozzle, means normally maintaining said plate in a position closing the second nozzle to produce an INHIBIT signal, and means for displacing the plate to open said second nozzle when the separated thread is at the notch to produce a NON-INHIBIT signal.
 9. A device according to claim 8 additionally comprising means providing a control signal in response to presence of both of said NO-GO and NON-INHIBIT signals.
 10. A device according to claim 8 additionally comprising means providing a control signal in response to presence of at least one of said GO and INHIBIT signals.
 11. A device according to claim 8 additionally comprising an OR/NOR fluidic gate having a supply port for connecting the gate to said pressure source, a first input port connected to receive said GO and NO-GO signals, a second input port connected to receive the INHIBIT and NON-INHIBIT signals, a first output port delivering an OR signal from the supply port in presence of at least one of said GO and INHIBIT signals, and a second output port delivering a NOR signal from the supply port in response to presence of both of said NO-GO and NON-INHIBIT signals. 